I would propose that certain types (packs) of Enkidukai are (capable) of growing manes... now whether they choose to treat this as hair, as fur, or simply trim it back to be 'normal' fur length is open for interpretation, but I think it's about the most logical way to say "Some do, some don't."
Personally, I prefer to envision them with actual hair or hair-like fur on their heads, but I haven't seen anything to suggest this is actually the case for Yliakum's felid race.